Bit pattern media (BPM) has been extensively explored by the magnetic recording industry as one of several key solutions to expand perpendicular magnetic recording (PMR) technology in high density disk drives (HDDs). A typical BPM media consists of two repeating zones—a data zone and a servo zone. Data zones consist of homogenous dots to store data bits. Servo zones consist of dots with various patterns to describe a location and address of information in the data zone. In the servo zone, dots need be arranged into various pattern and spacings to encode information such as head position, timing, and tracking following information for a respective data zone.
The storage capacity of BPM is dependent upon the density of the magnetic islands, or “bits” on the media substrate surface. Current processes for achieving high density patterned media include imprint mold fabrication, nano-imprinting and pattern transfer into magnetic dots, and the like.
Self-assembling block copolymer (BCP) enables high-density lithographic bit patterning capability and is a promising material for BPM template fabrication. Directed self-assembly combines ‘top-down’ lithography (pre-registered pattern) and ‘bottom-up’ self-assembling materials like block copolymers. Directed self-assembly may generate ultra-high density homogenous patterns.